The integrated control of cardiovascular homeostasis is achieved through a combination of both direct neuronal control and systemic neurohormonal activation. Although the resultant release of both contractile and relaxant factors is normally under stringent regulation, an aberration in this status quo can result in cardiohemodynamic dysfunction with pathological consequences.
The principal mammalian vasoactive factors that comprise this neurohumoral axis are angiotensin-II, endothelin-1, and norepinephrine, all of which function via an interaction with specific G-protein coupled receptors (GPCR). Urotensin-II, represents an important member of this neurohumoral axis.
In the fish, this peptide has significant hemodynamic and endocrine actions in diverse end-organ systems and tissues:    both vascular and non-vascular (smooth muscle contraction) including smooth muscle preparations from the gastrointestinal tract and genitourinary tract. Both pressor and depressor activity has been described upon systemic administration of exogenous peptide.    osmoregulation effects which include the modulation of transepithelial ion (Na+, Cl−) transport.
Although a diuretic effect has been described, such an effect is postulated to be secondary to direct renovascular effects (elevated GFR); urotensin-II influences prolactic secretion and exhibits a lipolytic effect in fish (activating triacylglycerol lipase resulting in the mobilization of non-esterified free fatty acids) (Person, et al. Proc. Natl. Acad. Sci. (U.S.A.) 1980, 77, 5021; Conlon, et al. J. Exp. Zool. 1996, 275, 226); human Urotensin-II has been found to be an extremely potent and efficacious vasoconstrictor; exhibited sustained contractile activity that was extremely resistant to wash out; and had detrimental effects on cardiac performance (myocardial contractility). Human Urotensin-II was assessed for contractile activity in the rat-isolated aorta and was shown to be a very potent contractile agonist. Based on the in vitro pharmacology and in vivo hemodynamic profile of human Urotensin-II, it plays a pathological role in cardiovascular diseases characterized by excessive or abnormal vasoconstriction and myocardial dysfunction. (Ames et al. Nature 1990, 401, 282.)
Compounds that antagonize the Urotensin-II receptor may be useful in the treatment of congestive heart failure, stroke, ischemic heart disease (angina, myocardial ischemia), cardiac arrhythmia, hypertension (essential and pulmonary), COPD, fibrosis (e.g. pulmonary fibrosis), restenosis, atherosclerosis, dyslipidemia, asthma, neurogenic inflammation and metabolic vasculopathies all of which are characterized by abnormal vasoconstriction and/or myocardial dysfunction. Urotensin antagonists may provide end organ protection in hypersensitive cohorts in addition to lowering blood pressure.
Since Urotensin-II and GPR 14 are both expressed within the mamamalian CNS (Ames et al. Nature 1999, 401, 282), they also may be useful in the treatment of addiction, schizophrenia, cognitive disorders/Alzheimers disease, impulsivity, anxiety, stress, depression, pain, migraine, neuromuscular function, Parkinsons, movement disorders, sleep-wake cycle, and incentive motivation.
Functional Urotensin-II receptors are expressed in rhabdomyosarcomas cell lines and therefore may have oncological indications. Urotensin may also be implicated in various metabolic diseases such as diabetes and in various gastrointestinal disorders, bone, cartilage, and joint disorders (e.g., arthritis and osteoporosis); and genito-urinary disorders. Therefore, these compounds may be useful for the prevention (treatment) of gastric reflux, gastric motility and ulcers, arthritis, osteoporosis and urinary incontinence.
CCR-9, a seven transmembrane, G-protein-coupled chemokine receptor was recently identified as the physiologic receptor for CCL25/thymus-expressed Chemokine (TECK). CCR-9 is mainly expressed in thymocytes and T lymphocytes from the small intestine and colon. CCL25/TECK is predominantly expressed in the thymus and small intestine. Studies have shown that CCR-9 mediates chemotaxis in response to CCL25/TECK is likely to play an important role in regulating the trafficking of developing T cells within the thymus and be critical for the development, homeostasis, and/or function of mucosal T lymphocytes.
It has been shown that CCR-9+ lymphocytes were markedly elevated in peripheral blood lymphocytes in patients with small bowl Crohn's or celiac disease. TECK expression is altered in an inflamed small bowel, being intensely expressed in a patchy distribution in crypt epithelial cells in proximity to lymphocytic infiltrates. Neutralization of TECK inhibits homing of CD8+ T cells to the IEL (intraepithelial lymphocyte) compartment. This directly demonstrates that CCL25 and CCR-9 function in recruiting effector lymphocytes to the small intestinal epithelium following their activation in gut-associated lymphoid tissue (GALT).
Targeting CCL25/TECK and/or CCR-9 may provide a way to selectively modulate small-intestinal immune responses as suggested by the fact that activated CCR-9(+) CD8alphabeta(+) lymphocytes selectively localized to the small-intestinal mucosa, and in vivo neutralization of CCL25/TECK reduced the ability of these cells to populate the small-intestinal epithelium These results demonstrate an important role for chemokines in the localization of T lymphocytes to the small-intestinal mucosa. (Svensson et al., J. Clin. Invest., 2002, 110:1113-21)
CCR-9 receptor expression on human eosinophils from peripheral blood and bronchoalveolar lavage fluid after setmental antigen challenge was reported recently (Liu et al, J Allergy Clin Immunol. 2003 September; 112(3):556-62). CCR-9 was also found to selectively express on T-ALL CD4+ T cells and moderately express on T-CLL CDR+ T cells. CCL25/TECK selectively induced T-ALL CD4+ T cell chamotaxis and adhesion (Qiuping et al., Cancer Res. 2003 Oct. 1; 63(19):6469-77. Annels et al., Blood 2003 Dec. 4 [Epub ahead of print]). A recent study also demonstrates an increase in the expression of CCR-9 on peripheral blood gammadelta T cells in individuals having HIV-1 infection (Poles et al., J Virol. 2003 October; 77(19):10456-67).